1. Field of the Invention
This invention relates, generally, to medical devices. More specifically, it relates to a device for checking and verifying the number of seeds and spacers loaded inside a brachytherapy seed implantation needle.
2. Description of the Prior Art
It is easy for a physician implanting radioactive seeds in a prostate gland or other tissue to lose count of the number of seeds that have been implanted in a procedure. The number of seeds to be planted is usually a large number, and the difficulty of maintaining an accurate count of the seeds while performing the procedure is obvious.
If the physician receives a pre-loaded needle from a physicist or nuclear pharmacy, he may want to verify the count within the needle. He has no alternative other than unloading and reloading the needle within the operating room or X-raying the needle. Both methods are time consuming and therefore costly, especially since it requires hand loading of the radioactive seeds back into their cartridge. Nor is the handling of the seeds desirable.
One solution to the seed-counting problem is disclosed in a brachytherapy needle loading device called the xe2x80x9cExpress Loaderxe2x80x9d developed by Indigo Medical, Inc., of Cincinnati, Ohio, a Johnson and Johnson Company. That device provides a sliding radiation shield that enables magnified, see-through verification of the number of seeds to be loaded into the needle. More particularly, the seeds are housed in a plastic, transparent or at least translucent housing and that housing is covered by a cylindrical radiation shield. When the shield is telescopically retracted with respect to the housing, the number of seeds in the housing may be counted.
However, this express loader is expensive and only offered to certain physicians if they buy the seeds and loading service supplied by Johnson and Johnson.
What is needed, then, is a brachytherapy seed verification system that enables a physician to count the number of seeds and spacers within the pre-loaded needle to verify the correct number without requiring removal of the seeds and manually reloading the needle.
However, in view of the prior art taken as a whole at the time the present invention was made, it was not obvious to those of ordinary skill in this art how the needed device could be provided.
The long-standing but heretofore unfulfilled need for a brachytherapy verification device that enables the counting or visual verification of the seeds and spacers within a brachytherapy needle includes a needle having a sharp distal end and a lumen adapted to slidingly receive therein a plurality of said seeds and spacers. An adapter means such as a LUER LOK(copyright) adapter is secured to a proximal end of the needle. A clear plastic tube has a distal end received within a hollow interior of the adapter means and a hub aligns a lumen of the tube with the lumen of the needle. An elongate plunger rod is adapted to be slideably introduced into the lumen of the tube from a proximal end of the tube. The clear plastic tube has a lumen of substantially the same diameter as the lumen of the needle. When the assembly is positioned with the distal end of the needle pointing upwardly, and the plunger rod is retracted so that it does not occupy the lumen of the clear plastic tube, the seeds and spacers within the lumen of the needle slide under the influence of gravity into the lumen of the tube. The number of said seeds and spacers may then be visually ascertained by inspection of the contents of the clear plastic tube.
The hub is secured to a proximal end of the adapter means and serves to align the lumen of the clear plastic tube with the lumen of the needle.
The novel method for checking and verifying the number of seeds and spacers in a brachytherapy needle includes the steps of mounting an adapter means of hollow construction to a proximal end of an elongate needle. A distal end of a clear plastic tube is inserted into a proximal end of the adapter means. The lumen of the needle and the lumen of the clear plastic tube are dimensioned so that the lumens share a common diameter and abut each other. The lumen of the clear plastic tube is aligned with the lumen of the needle. A plunger rod is adapted to be slidingly introduced into a proximal end of the clear plastic tube, but it is substantially withdrawn from the clear plastic tube when the seeds and spacers are to be verified. The distal end of the needle is then pointed upwardly so that seeds and spacers in the lumen of the needle slide therefrom under the influence of gravity into the lumen of the clear plastic tube. The quantity of the seeds and spacers is then visually ascertainable.
A second embodiment includes an assembly that enables visual verification of bone wax, seeds, and spacers in a brachytherapy needle. It includes a needle having a sharp distal end and a lumen adapted to slidingly receive therein bone wax and a plurality of radioactive seeds and spacers. An adapter means of hollow construction is secured to a proximal end of the needle. A stylet adapted to be slidingly introduced into a proximal end of the adapter means and hence into a proximal end of the needle is provided. The assembly further includes a clear plastic tube having a lumen of sufficient diameter to slidingly receive therewithin the needle and an elongate plunger rod adapted to be slideably introduced into the lumen of the clear plastic tube from a proximal end thereof. The hub of the first embodiment is not present in the second embodiment.
The method of the second embodiment includes the steps of mounting an adapter means of hollow construction to a proximal end of an elongate needle. A clear plastic tube having a lumen of sufficient diameter is provided to slideably receive the elongate needle. A plunger rod having an external diameter less than the diameter of the lumen of the needle is provided and introduced through the lumen of the clear plastic tube and into the lumen of the needle. The plunger is substantially withdrawn from the lumen of the clear plastic tube when the seeds and spacers are to be verified. The distal end of the needle is pointed downwardly so that seeds and spacers in the lumen of the needle slide therefrom under the influence of gravity into the lumen of the clear plastic tube so that the quantity of said seeds and spacers is visually ascertainable.
A second method performed by the assembly of the second embodiment includes a method of checking and verifying the bone wax that seals the seeds and spacers in the needle during transportation as well as the number of seeds and spacers. This method includes the steps of mounting an adapter means of hollow construction to a proximal end of an elongate needle. A clear plastic tube having a lumen of sufficient diameter to slideably receive the elongate needle is provided. Also provided is a plunger rod having an external diameter less than the diameter of the lumen of the clear plastic tube. The plunger rod is adapted for sliding introduction into the lumen of the clear plastic tube. The plunger rod is substantially withdraw from the lumen of the clear plastic tube and a stylet is introduced into a proximal end of the elongate needle. The stylet pushes a string of bone wax, seeds and spacers out of the lumen of the elongate needle and into the lumen of the clear plastic tube so that the bone wax, seeds, and spacers may be visually verified. The string of bone wax, seeds and spacers is pushed out of the clear plastic tube and into the lumen of the elongate needle by introducing the plunger rod into a proximal end of the clear plastic tube. The clear plastic tube and the plunger rod are then removed so that the elongate needle is usable in a brachytherapy procedure.
An important object of this invention is to significantly advance the art of brachytherapy needles by providing a brachytherapy needle construction that enables a physician to quickly and accurately ascertain the number of unimplanted radioactive seeds without removing the seeds from the needle.
Another object is to provide an easy method for visually ascertaining a string of bone wax, seeds, and spacers in a brachytherapy needle.
The invention accordingly comprises the features of construction, combination of elements, and arrangement of parts that will be exemplified in the description set forth hereinafter, and the scope of the invention will be set forth in the claims.